Exemplary embodiments of the invention relate to a solid bowl screw centrifuge.
German patent document DE 43 20 265 A1 and PCT International patent document WO 2004/058409 A1 disclose solid bowl screw centrifuges.
German patent document DE 42 38 568 A1 illustrates in FIG. 1 how dirt can accumulate in a solids capture chamber when a solid bowl screw centrifuge is in operation. This necessitates repeated cleaning of the solids capture chamber in order to avoid operating impairments caused by blockages or even damage to the rotating system.
To solve this problem, U.S. Pat. No. 3,399,828 discloses forming at the solids discharge of a solid bowl screw centrifuge, at its tapering end, a solids capture chamber in which is arranged, tension-mounted, an elastic air-impermeable diaphragm covering an air duct that is closed off, air-tight, with respect to the surroundings and with respect to the actual solids capture chamber. By the action of compressed air, pressure fluctuations can be generated at the diaphragm which set the latter in oscillation, thus serving to release dirt from the walls of the capture chamber, here the diaphragm.
Although the problem of dirt is reduced in this way, the problem still appears to be the relatively high outlay in terms of apparatus and structure for generating pressure fluctuations at the elastic diaphragm. Furthermore, it is relatively difficult to change the diaphragms, since the diaphragms repeatedly have to be mounted, pressure-tight, in the solids capture chamber.
Exemplary embodiments of the invention are directed to eliminating this problem.
According to the invention, advantageously, in spite of dispensing with a chamber that is closed by an elastomer and in which a pressure gradient can be generated by the action of compressed air, movements in the elastomeric element in the solids capture chamber are sufficiently generated, solely by the impact of the solid, in order to release dirt. The number of cleanings of the solids capture chamber can consequently be reduced, compared with solids capture chambers without an elastomeric element. Moreover, maintenance work is simplified as compared with solutions with a pressure chamber in which a pressure gradient can be generated, since the elastomer no longer has to be arranged so as to be pressure-tight. Moreover, as compared with such solutions, there is no need for the means required for generating the pressure gradient (for example, a controllable pump).
A further advantage is the noise reduction achieved, since the impingement momentum of the solids is effectively decoupled vibrationally from the stand or the noise-radiating surface of the centrifuge, and since the hose segment implements a dual-shell structure which has a noise-insulating effect. This is also advantageous especially in the case of harder and coarse solids and when there is a high discharge of solids for a unit time (or high solids performance).